Elongated materials (sometime referred to as continuous) in the form of films, sheets, ribbons, tows, etc. obviously have many known uses. For example, film or sheet material is useful in the packaging art. As another example, tow (a bundle or band of many fibers of small diameter) is useful in the production of filters. Tow may be formed into semi-rigid rods of various densities and stiffness and used as filter material. In working with such elongated material, there are occasions when a splice needs to be made, because the associated machinery is designed to be operated on a continuous basis. If there should be a break in the feed of elongated material, time-consuming operations such as rethreading and returning to normal operating rate are required. Interruptions in the continuity of the material may result from breaks in the material, equipment malfunction, or possibly change-over from one container to another. Therefore, for reasons of production efficiency, it can be important to attach a leading end of one length of elongated material to the trailing end of another length to insure continuity of operation.
Splices made by prior-art devices generally produce highly visible, charred defects across elongated material such as tow. For example, in U.S. Defensive Publication T913,005 "Method of Tow Splicing", a method is described which is useful for splicing tows and the like. The sections of tow to be joined are placed one above the other in an essentially parallel "side-by-side" relationship. One such section is located in contact with a suitably mounted wire and a clamping means is caused to contact the other tow section. While thus clamped an electrical current is passed through the wire, causing it to heat up and melt the two tow sections, producing a highly-visible, charred splice which is oriented across the tow in a substantially perpendicular relationship to the long axis of the spliced tow. Such splices are useful for various purposes, such as joining tow from the bottom of one bale to tow from the top of a new bale to facilitate the continuation of operation of the plugmaker machinery, etc. However, the splices created by this prior-art method are totally unsuitable for use in some cases such as filters because they create highly-visible defects which do not bloom acceptably in subsequent passage through banding jets during conversion of the tow into filters. Thus, tow containing such prior-art splices is generally allowed to pass through the various stages of the processing machinery, such as a plugmaker, etc., and then the machinery is stopped and the product containing the splices is removed. After removal of the defective product or intermediate product, the processing machinery can be restarted. Such stop-and-start procedure causes loss of efficiency and can have an adverse effect on product quality.